The present invention relates to a method of manufacturing a semiconductor device and a semiconductor module. More particularly, the present invention relates to a method of manufacturing a semiconductor device allowing a semiconductor chip to be directly mounted on a circuit substrate having conductive patterns etc. formed on its surface and manufacturing a semiconductor module using such semiconductor device.
In recent years, there is an increasing need for miniaturization, light weight, and low profile of devices in the field of electronic devices. In addition, there is also an increasing need for miniaturization, light weight, and low profile of a semiconductor device as a component of these electronic devices.
For satisfying these demands, a technology called COB (Chip On Board) is presently put into practical use as one of technologies to mount semiconductor devices. The COB technology directly mounts a semiconductor chip on the circuit substrate where conductive patterns and the like are formed.
The following describes a COB package using the conventional COB mounting technology.
A conventional package comprises a circuit substrate where a conductive pattern is formed on its surface; a semiconductor chip arranged on the circuit substrate; a wire as a conductor to electrically connect an electrode of the semiconductor chip with the conductive pattern on a surface of the circuit substrate; a sealing frame that is provided on the circuit substrate and surrounds a region including a wire, part of the conductive pattern connecting with the wire, and the semiconductor chip; and a sealer comprising such as resin or the like injected in the sealing frame.
The sealing frame provided on the circuit substrate works as a dam for preventing an outflow of the sealer such as resin injected in the frame. This configuration reliably protects the wire, part of the conductive pattern connecting with the wire, and the semiconductor chip all of which need to be protected.
The conventional method of manufacturing COB packages arranges semiconductor chips made of a silicon wafer on the circuit substrate, for example. A known technology such as the wire bonding is used to electrically connects semiconductor chip electrodes and conductive patterns on the circuit substrate with each other.
Then, the sealer such as a sealing resin is used to seal the semiconductor chip, the wire, and part of the conductive pattern connecting with the wire mounted on the circuit substrate. In order to seal the semiconductor chip, the sealing frame defines a region that includes the semiconductor chip, the wire electrically connecting a semiconductor chip with a circuit substrate conductive pattern, and part of the conductive pattern connecting with one end of the wire. This sealing frame is provided at a specified position on the circuit substrate by using known printing and mounting methods. A fluid sealing resin is then injected into the sealing frame.
However, a COB-mounted semiconductor device according to the conventional manufacturing method provides each semiconductor device with the sealing frame to prevent the sealer from flowing out. The semiconductor chip is sealed by injecting the sealer into the sealing frame. Accordingly, an external dimension of each semiconductor device is restricted by the sealing frame provided on the circuit substrate, bottlenecking the miniaturization of semiconductor devices. In addition, the conventional method provides the sealing frame each time an individual semiconductor device is formed, increasing costs and the manufacturing time.
When a semiconductor module includes the COB-mounted semiconductor device according to the conventional manufacturing method, a sealing frame used for the COB mounting is arranged on a solder resist formed between the COB-mounted semiconductor device and an adjacently mounted semiconductor device. For this reason, a sealing frame width, misalignment of a solder resist mask, etc. affect a length of the solder resist provided between the COB-mounted semiconductor device mounted on the circuit substrate and the adjacently mounted semiconductor device. Consequently, a specified distance is inevitable between the semiconductor devices, making it difficult to miniaturize semiconductor modules.
It is therefore an object of the present invention to provide a method of manufacturing miniaturized COB-mounted semiconductor devices and semiconductor modules by decreasing costs and shortening the manufacturing time.
To solve the above-mentioned problems, a semiconductor device manufacturing method according to the present invention comprising: arranging a dam made of a highly heat-shrinkable material on a circuit substrate having at least one surface provided with a semiconductor element, a conductive pattern, and a conductor having one end connected to the semiconductor element and the other end connected to the conductive pattern, wherein the dam defines a region including the semiconductor element, the conductor, and the part of the conductive pattern connected to the other end of the conductor; injecting a sealer into a region defined by the dam and using the sealer to seal the semiconductor element, the conductor, and the part of the conductive pattern connecting with the other end of the conductor; and cooling the dam to remove it.
Another semiconductor device manufacturing method according to the present invention comprising: arranging a dam made of a highly heat-shrinkable material on a first circuit substrate having at least one first surface provided with a first semiconductor element, a first conductive pattern, and a first conductor having one end connected to the first semiconductor element and the other end connected to the first conductive pattern, wherein the dam defines a region including the first semiconductor element, the first conductor, and the part of the first conductive pattern connected to the other end of the first conductor; injecting a sealer into a region defined by the dam and using the sealer to seal the first semiconductor element, the first conductor, and the part of the first conductive pattern; cooling the dam to remove it; and arranging the removed dam on a second circuit substrate having at least one second surface provided with a second semiconductor element, a second conductive pattern, and a second conductor having one end connected to the second semiconductor element and the other end connected to the second conductive pattern, injecting a sealer into the removed dam arranged on the second circuit substrate, and using the sealer to seal the second semiconductor element, the second conductor, and part of the second conductive pattern connecting with the other end the second conductor.
Yet another semiconductor module manufacturing method comprising: arranging a dam made of a highly heat-shrinkable material on a circuit substrate having at least one surface provided with a semiconductor element, a conductive pattern, and a conductor having one end connected to the semiconductor element and the other end connected to the conductive pattern, wherein the dam defines a region including the semiconductor element, the conductor, and the part of the conductive pattern connected to the other end of the conductor; injecting a sealer into a region defined by the dam and using the sealer to seal the semiconductor element, the conductor, and the part of the conductive pattern; cooling the dam to remove it and forming a first semiconductor device mounted on the circuit substrate; and mounting a second semiconductor device on the circuit substrate, wherein the second semiconductor device is separated from the first semiconductor device for a specified distance.